The production of carbon dioxide in energy generation processes is becoming more and more of a problem worldwide. The increased concentration of carbon dioxide in the atmosphere results in reduced heat radiation from the Earth, which causes the temperature on Earth to rise and a number of life-determining processes to be perturbed. A solution for this problem can be sought in limiting the consumption of energy and, in addition, in forms of energy generation which do not yield carbon dioxide, such as combustion of hydrogen, nuclear energy and solar energy. The effect of solutions of this type is limited, certainly in the short and medium term, so that it is, at most, a question of reduced increase of the production of carbon dioxide.
When fossil fuels are gasified, the main products are hydrogen and carbon monoxide, the most desirable component of the two being hydrogen. The shift from carbon monoxide to hydrogen can be effected, for example, by treatment with water (steam). This again produces carbon dioxide which causes the problems outlined above.
Methods for removing carbon dioxide from gas streams do exist, but they have the drawback that they result in a considerable decrease (approximately 10%) of the efficiency of the energy generation (see K. Blok and C. A. Hendriks, "Voorstellen voor de integrerende studie ter afsluiting van het SOP CO.sub.2 " [Proposals for the Integrating Study at the close of the Coherent Research Package CO.sub.2 ]. State University of Utrecht, December 1991; Techniques for Absorption or Fixing of CO.sub.2, Technieuws Tokyo, volume 29 (1), May 1991, publication of the Dutch Ministry of Economic Affairs.
Japanese Patent Application 51-4090 discloses a process for removing water and CO.sub.2 from hot gases, in particular in the manufacture of steel, by treating the gases with CaO and/or MgO. The used oxide can be regenerated, according to this process, by hot air being passed through. In U.S. Pat. No. 3,516,808 a process is described for regenerating calcium oxide which has been used for removing CO.sub.2. According to Dutch Patent Application 82.02061 (=GB-A-2,103,645), CO.sub.2 and H.sub.2 S can be removed in a wet process from gases such as hydrocarbons by treatment with a solution of a tertiary amine and a physical absorbent. Japanese Patent Application 61-146344 discloses a process wherein CO.sub.2 and water are removed from inert gases by utilising a zeolite bed which is regenerated by heating with combustion gases of a catalysed combustion of propane.